import config from './../../config.js';
import Base_layers_class from './../../core/base-layers.js';
import Dialog_class from './../../libs/popup.js';
import alertify from './../../../../node_modules/alertifyjs/build/alertify.min.js';

class Tools_restoreAlpha_class {

    constructor() {
        this.POP = new Dialog_class();
        this.Base_layers = new Base_layers_class();
    }

    restore_alpha() {
        var _this = this;

        if (config.layer.type != 'image') {
            alertify.error('图层必须是图像，将其转换为栅格来应用此工具。');
            return;
        }

        var settings = {
            title: 'Restore alpha',
            preview: true,
            on_change: function(params, canvas_preview, w, h) {
                var img = canvas_preview.getImageData(0, 0, w, h);
                var data = _this.recover_alpha(img, params.level);
                canvas_preview.putImageData(data, 0, 0);
            },
            params: [
                { name: "level", title: "Level:", value: "128", range: [0, 255] },
            ],
            on_finish: function(params) {
                window.State.save();
                _this.save_alpha(params.level);
            },
        };
        this.POP.show(settings);
    }

    save_alpha(level) {
        //get canvas from layer
        var canvas = this.Base_layers.convert_layer_to_canvas(null, true);
        var ctx = canvas.getContext("2d");

        //change data
        var img = ctx.getImageData(0, 0, canvas.width, canvas.height);
        var data = this.recover_alpha(img, level);
        ctx.putImageData(data, 0, 0);

        //save
        this.Base_layers.update_layer_image(canvas);
    }

    recover_alpha(data, level) {
        var imgData = data.data;
        var tmp;
        level = parseInt(level);
        for (var i = 0; i < imgData.length; i += 4) {
            tmp = imgData[i + 3] + level;
            if (tmp > 255) {
                tmp = 255;
            }
            imgData[i + 3] = tmp;
        }
        return data;
    }

}

export default Tools_restoreAlpha_class;